Inspired by Undateable, a wickedly funny new guide to the style mistakes men make, O takes on six self-sabotaging guys—nominated by the women who love them—and shows them six ways to improve their look.

By Katherine B. Weissman

1 of 6

1. LOSE THE SLACKER LOOK

Robb Tennant, 29, with girlfriend Jacqueline Nicholls

Before: Too much facial hair is one of Undateable's main deal breakers. But for Robb, a musician with the alternative-folk band Rooftops, not shaving was a symbol of mourning based on Jewish ritual: His mother died five years ago, and he found it tough to move on. Robb's teenage clothes also needed to evolve. "I'd like him to look more clean-cut and sophisticated," says girlfriend Jacqueline, a fashion designer.

After: "From Amish farmer to Robert Redford!" raves Anne Coyle, coauthor of Undateable. The suit is slightly rumpled, so he looks hip, not stiff, and his shoes are worn sockless. Contacted a month after his transformation, Robb reports a "92 percent positive response" to his absent beard (just like a guy to quantify): "I expected teasing and jabbing, but people are surprisingly supportive."